This invention relates generally to secondary storage batteries and particularly to lead-acid type storage batteries having through the partition intercell connections.
In recent years, the lead-acid storage battery industry has developed an intercell connection in batteries in which electrical connection between adjacent battery plate elements in battery cells is made by electrically joining the elements through the battery partition walls. This type of intercell connection is seen in U.S. Pat. Nos. 3,793,086 issued Feb. 19, 1974 to Badger; 3,869,316 issued Mar. 4, 1975 to Matter; No. 3,313,658 issued Apr. 11, 1967 to Sabatino et al and No. 3,897,269 issued July 29, 1975 to Sabatino et al, both assigned to the assignee of the present invention. The intercell connections described in the aforementioned patents basically relate to automotive type lead-acid batteries having a plurality of cells with each cell including a plurality of alternating negative and positive battery plates. The negative plates in each cell have protruding lugs which are joined together by electrically conductive connecting straps. Similarly, the positive plates in each cell have lugs which are joined by straps as well. The straps connecting the positive and negative plates are provided with an upstanding lug. The upstanding lug from a group of positive or negative plates in one cell is aligned with the upstanding lug on the group of opposite polarity plates in the adjacent cell. An aperture is provided in the cell partition wall and the lugs are joined together through the partition wall by welding to provide a connection through the aperture. The types of batteries with which these patents are concerned are adapted for use in automotive vehicles to perform such functions as providing starting, lighting and ignition. Conventionally, such batteries include a minimum number of seven or more plates in each cell. As a practical necessity within the cells, straps must be provided to couple the lugs of similar polarity plates. While Canadian Pat. No. 873,522 issued June 15, 1971 to Matter proports to show an intercell connection of a plurality of plates by directly welding a plurality of lugs together, it has been applicant's experience that such a construction is impractical for mass production of batteries. This is because the welding technique utilized to join the lugs relies upon resistance welding whereby high resistance between juxtapositioned lead parts results in generation of sufficient heat to melt the adjoining lead pieces and fluidize the lead to cause fusion. In the case of a plurality of parts having two or more interfacing surfaces, fusion does not reliably always take place at all interfaces whereby defective connections could result. It has been found that the most desirable intercell welding thus requires no more than two surfaces to be joined.
Conventional lead-acid automotive type batteries are also of an excessive capacity from that required to start small engines such as used in riding mowers, snow blowers, and the like. Such batteries generally require a fewer number of plates than are normally contained in an automotive type battery in order to provide adequate service.